I think that most of the expats are with CHC Africa or CHC Global and are leased together with some aircraft to Sonair. Heli Union also did have some expats flying leased S76s flying in Sonair clours and on the D2 register but don't know whether they still do.
I know of a couple of expats who did approach Sonair directly but were turned down, although that was a couple of years ago now.